Internal combustion engine

ABSTRACT

A radial internal combustion engine comprising pairs of diametrally opposed cylinders, the pistons of which act on a central cam to rotate a shaft. Each piston head carries at least one intake or exhaust valve actuated by the same cam.

9 1 1 Unite tates atent 1 1 3,584,610

[72] Inventor Kilburn I. Porter 1,115,477 11/1914 Austin 1. 123/47 A R0.Box 547,Evanst0n. Wye. 82930 1.765.237 6/1930 King 123/55 A [21] APPLNO,879,734 1,830 O46 11/1931 White M l23/55 AA Filed 1969 FOREIGN PATENTS{451 Paemed 1971 354,535 7/1905 France 123/44 E 432,114 9/1911 France ll l23/47A France v l v i E 9 Claims, 9 Drawing Figs. PrimaryExaminerWendell E. Burns 52 U.S. c1 l23/55AA, AmmekHolcombe, wetheriBrisebis 123/44 E, 123/47 R, 123/56 C [51] Int. Cl ..F02b 75/22, F01111/00, F02b 75/04 [50] Field of Search l23/47,47

A, 47 AA, 47 AB, 55 AA, 44 15,56 C

ABSTRACT: A radial internal combustion engine comprising [56] Referencescited pairs of diametrally opposed cylinders, the pistons of whichUNITED STATES PATENTS act on a central cam to rotate a shaft. Eachpiston head carries 679,876 8/1901 Blake v. 123/47 at least one intakeor exhaust valve actuated by the same cam.

/6 3/ za I9 27 5 PATENTEU Jum 5 m SHKET 1 Ci PATENTED JUN] 51% SHEET 2[IF 2 m, AlHI INTERNAL COMBUSTION ENGINE SUMMARY OF THE INVENTION Theinvention relates to an internal combustion engine having an even umberof cylinders and pistons arranged in a circle, with the pistons indiametrically opposed pairs, and the pistons of each pair attached toeach other.

Internal combustion engines of this type a shown in US. Pat. Nos.1,765,237 and 1,830,046. These engines comprise cylinders and pistonsarranged in a circle and the pistons reciprocate in the plane of thatcircle. All the pistons are connected to drive a three-lobe cam fixed toa rotary shaft. This cam converts the reciprocating movement of thepistons into rotary motion. The intake and exhaust valves of thecombustion chambers formed by the cylinders and pistons extend throughthe walls of the cylinders and are actuated by separate rod and leverarrangements.

In another known type of internal combustion engine shown in US. Pat.No. 679,876 and having cylinders and pistons arranged in a circle, thereciprocating movement of the pistons is converted into rotary motion bymeans of a crank. The exhaust valves extend through the pistons and areactuated by a cam mounted on the same shaft as the piston rods andrevolving with the crank. Thus, both a crank and a revolving cam arerequired for four cylinders with valved pistons arranged in a circle.

It is the object of the present invention to provide an internalcombustion engine with an even number of cylinders and pistons arrangedin a circle, which uses a single multilobe cam both for the conversionof the reciprocating movement of all the pistons into a rotary motionand for the actuation of either the intake valves or the exhaust valvesextending axially through the pistons.

It is a further object of the invention to provide a am for saidinternal combustion engine having two cam surfaces, which cooperate witha pair of rollers mounted on the bottom of each piston so thatreciprocation of the pistons causes rotation of the cam, and another camsurface which actuates the valves extending through the pistons.

Yet another object of the invention is to provide a multilobe cam for aninternal combustion engine having an even number of cylinders andpistons arranged in a circle and in which both the intake and theexhaust valves extend through the pistons.

Other objects will be apparent from the following description of twoembodiments of the invention, with reference to the accompanyingdrawings, in which:

FIG. 1 is a diagrammatic elevational view of an internal combustionengine according to the invention with one end of the cylinder blockbroken away to expose the pistons;

FIG. 2 is a sectional view taken along the line 11-11 of FIG. 1;

FIG. 3 is a fragmentary sectional view taken along the line 111-111 ofFIG. 1;

FIG. 4 is a top view of a three-lobe cam used in the internal combustionengine according to the invention;

FIG. 5 is a side view ofthe cam of FIG. 4;

FIGS. 6 and 7 are detailed views showing two connected pistons used inthe internal combustion engine according to the invention;

FIG. 8 is a fragmentary view of a piston for a second embodiment of theinvention; and

FIG. 9 is a side view of a three-lobe cam for the second embodiment ofthe invention.

FIG. 1 shows an internal combustion engine according to the inventioncomprising a cylinder block l having four cylinders 2, 3, 4, 5. Eachcylinder is provided with an exhaust port 6, 7, 8, 9 for the burned gas.The valves for these ports are not shown since they are of aconventional construction well known to those skilled in the art. Ineach cylinder 2, 3, 4, 5, a piston 12, 13, 14, is mounted forreciprocating movement and closes one end of a combustion chamber inthat cylinder. The combustion chambers are sealed by piston rings 16.The opposed pistons 12, 14 and 13, 15 of each pair are connected to eachother by slotted plate members, as shown in FIGS. 6 and 7 for pistons13, 15 which are connected by plate members 17 and 19 attached to thepistons by pins 21 and 23 which extend through the pistons, transverselyto the axes thereof. Pistons 12 and 14 are connected by slotted platemembers 18 and 20 (FIGS. 1 and 3) in the same manner as pistons 13 and15. However, the plate members 18 and 20 are further from the planecomprising the axes of all the pistons than the plate members 17 and 19ofpistons 13 and 15 (FIGS. 2 and 3). Two rollers 25 and 27, 26 and 28,29 and 31, 30 (the second roller of the latter pair is not shown) arejournaled on each of the pins 21, 22, 23, 24 by means of which the platemembers are attached to the pistons.

Intake valves extending coaxially through the pistons comprise a valvestem 32 carrying a slotted guide member 33 and a plate 34. The intakevalves also comprise a valve disc 36 on the outer end of the valve stem32 and a valve lifter 37 on the inner end of the guide member 33. Thevalve stems 32 may consist of two parts screwed together at 38 in orderthat the valves can be inserted in the pistons and a spring 39 can bemounted between the plate 34 and the inner surface of the pistoncoaxially of the valve stem 32 so that the spring 39 biases the intakevalve toward a closed position.

A three-lobe cam 40 is fixed at its center to a rotary shaft 41 in thecylinder block 1. This rotary shaft extends through the cam 40 andthrough slots 42, 43, 44, 45 in the plate members 18, 17, 20, 19 and isjournaled in the cylinder block (not shown in detail), and at least oneend of the rotary shaft 41 projects out of the cylinder block. As shownin FIGS. 2 and 3, the three-lobe cam lies between the plate members 17,18 and 19, 20 and rotates with the rotary shaft 41.

At first, movement of the pistons .and the three-1obe cam will bedescribed without consideration of the function of the valves. Whenpiston 14 moves inward (i.e. when the volume of the correspondingcombustion chamber increases) piston 15 also moves inward. Pistons 12and 13 simultaneously move outward and the three-lobe cam 40 rotates ina clockwise direction (FIG. 1). The rollers of all the pistons arealways in contact with first cam surfaces 46 and 47 of the three-lobecam 40. The position of these cam surfaces can be seen best in FIGS. 3,4 and 5. When the pistons 14 and 15 move further inward, the rollers 29and 31 of piston 15 reach the lowest point on the first cam surfaces 46,47 (i.e. the point on the first cam surfaces nearest the rotary shaft41) after rotation of the three-lobe cam 40 through a small angle andthe piston 15 is in the so-called crank-end dead center position. Atthis moment the rollers 25 and 27 of piston 13 are in contact with thehighest point on the three-lobe cam, which lies opposite said lowestpoint, and the piston 13 is in the so-called head-end dead centerposition. Pistons l3 and 15 now reverse their direction of movement, andpiston 13 moves inward and piston 15 moves outward, while the rollers ofsaid pistons remain in contact with the first cam surfaces 46, 47 of thethree-lobe cam 40. Pistons 12 and 14 reciprocate correspondingly.Consequently, the reciprocating movement of the pistons 12, 13, 14, 15is converted into rotary motion of the shaft 41 by the three-1obe cam40.

As mentioned above, the cylinders 2, 3, 4, 5 are provided with exhaustports 6, 7, 8, 9, respectively, for the burned gas. The fuel to becompressed and to be burned is supplied through supply ports 10 and 11in the cylinder block 1. A blower may be used to produce an excesspressure in the crankcase, i.e. in the space surrounding the three-lobecam 40. (Details of the fuel supply and the supply ports are not shownSince they are known to those skilled in the art.) The above-describedintake valves extend through the pistons 12, 13, 14, 15 to admit fuelfrom the space surrounding the threelobe cam tothe combustion chambers.Those intake valves are normally held closed by the springs 39 and willbe opened only to admit fuel in a manner which will be described later.After that the valve will be closed again and the fuel is compressed byoutward movement of the piston and then ignited by a spark plug (notshown). The explosion drives the piston inward and the correspondingexhaust port in the cylinder is opened so that the burned gas flows outof the combustion chamber. At the same time, or a short time after that,fuel is forced into the combustion chamber again.

The three-lobe cam 40 has a second cam surface 48 between each two lobeswhich lies axially between the first cam surfaces 46 and 47, as seen inFIG. 5. The radius of curvature of the second cam surface 48 is largerthan that of the first cam surfaces 46, 47 (FIG. 4). The second camsurface is also shorter than the first cam surfaces and merges intothose first cam surfaces at the end of the lobes (FIGS. 4 and 5). Thissecond cam surface serves to actuate the intake valves by sliding thevalve lifter 37, the slotted guide piece 33, the valve stem 32 and thevalve disc 36 outward. This will be described in connection with anoperating cycle of piston 13.

In FIG. 1, piston 13 is nearly in head-end dead center position, justbefore ignition of the compressed fuel. This ignition occurs when therollers 25, 27 are in contact with the highest point on the three-lobecam 40. The explosion drives the piston inward and the rollers 25, 27are urged against the first cam surfaces 46, 47, so that the three-lobecam is rotated in a clockwise direction. Piston 13 then reaches theposition shown in FIG. I for the piston 14. When piston 13 moves furtherinward, the valve lifter 37 contacts the second cam surface 48 of thethreelobe cam and the valve lifter, the valve stem 32 and the valve disc36 are moved outward against the tension of the spring 39 so that theintake valve begins to open, as shown in FIG. 1 for pistons and 12, andin FIG. 2 for piston 15. Now fuel flows into the combustion chamber fromthe space surrounding the three-lobe cam 40. After further rotary motionthe valve lifter 37 reaches the end of he second cam surface 48 and isno longer in contact with the three-lobe cam, and the spring 39 closesthe intake valve. Outward movement of the piston then compresses thefuel in the combustion chamber and thus prepares it for ignition.

After the explosion the piston moves radially inward and the exhaustport opens, as shown for port 9 in cylinder 5, thereby releasing theburned gas.

In a practical example of the embodiment described having a 3-inchpiston stroke the rollers on the piston have a radius of 1.5 inches andthe highest points on the three-lobe cam are tangent to a circle havinga radius of 4.5 inches. The radius of curvature at the highest points ofthe three-lobe cam is 0.75 inch, and the radius of curvature of thefirst cam surfaces is 3 inches between each two lobes of the cam, thecenters of the latter curvatures lie on the same circle as the highestpoints of the cam. In another practical example having a 2-inch pistonstroke, the rollers have a radius of 1 inch, the highest points of thecam lie on a circle having a radius of 3 inches, the radius of curvatureat the highest points is 0.5 inch, and the radius of curvature of thefirst cam surfaces between each two lobes is 2 inches. Consequently, theratio of the magnitude of the stroke to the radius of the rollers to theradius of the circle of the highest points of the cam to the radius ofcurvature at the highest points on the lobes to the radius of curvatureof the first cam surfaces between each two lobes may be x to x/2 to 1.5xto x/4 to x.

In the first embodiment illustrated the lowest point on the second camsurface 48 lies exactly halfway between each two lobes of the three-lobecam, and both ends of the second cam surface 48 merge into the first camsurfaces 46, 47 at the same distance from said lowest point (FIGS. 4 and5). Therefore, the intake valve opens during the inward movement of thepiston and is kept open at the crank-end dead center position and duringa part of the outward movement. The exhaust port in the cylinder isopened during part of the time the intake valve is open. Therefore, theengine operates substantially as a two-stroke internal combustionengine. However, it is possible to locate the second cam surface awayfrom the midpoint between the highest points of each two lobes, so thatthe valve lifter first contacts the second cam surface at the crank-enddead center position of the piston or contacts it even later. The secondcam surface can be adjusted so that it will not open the intake valveextending through the piston until the exhaust port in the cylinder isclosed again. The operation will then resemble that of a four-strokeinternal combustion engine.

In the foregoing description the intake valves extend through thepistons while the exhaust valves are in the cylinder. It is alsopossible to locate the intake valves in the cylinders while the exhaustvalves extend through the pistons. Then the second cam surfaces have toopen and to close the exhaust valves during the predetermined period andin correct relation to the function of the intake valves.

Furthermore, both intake and exhaust valves may be arranged to extendaxially through the pistons. FIG. 8 is a fragmentary view of a pistonwith intake valve 49 and exhaust valve 56). The remainder of the pistonis similar to the pistons if FIGS. 1-3, 6 and 7. The intake and exhaustvalves 49, 50 extending through the piston are actuated by a three-lobecam with a second cam surface 48' and a third cam surface 51. Thesurface between two lobes of this three-lobe cam is shown in FIG. 9.

The rollers of the piston run on the first cam surfaces 46 and 47'. Thethird cam surface 51 opens the exhaust valve 50 to release burned gaswhile the inlet valve 49 is kept closed by the tension of a spring.After further rotation of the three-lobe cam the intake valve is closedand compression of the fuel begins.

When both intake and exhaust valves extend through the piston, thecrankcase must be divided into two sealed chambers, e.g. by a membrane,to separate the burned gas flowing through the exhaust valve from thefuel.

To control the opening of the intake and exhaust valves when both extendthrough the piston (FIG. 8) the second and third cam surfaces may beginand/or end at different points or at the same points of the three-lobecam and they may have the same or different radii of curvature.

In the illustrated embodiments each piston has two rollers and there aretwo first cam surfaces on the three-lobe cam for those rollers. However,the pistons may have only one roller or more than two rollers, and thethree-lobe cam may have a corresponding number of first cam surfaces.Furthermore, the engine according to the invention may comprise only twopistons and cylinders or more than four pistons and cylinders.

What I claim is:

1. In an internal combustion engine comprising a cylinder block, an evennumber of cylinders in said block arranged in a circle, said cylindersbeing positioned in diametrically opposed pairs, a piston in eachcylinder, means connecting the pistons of each pair to each other, ashaft rotatably mounted in said block and carrying a multilobe cam, anddrive means carried by each piston in contact with said earn, theimprovement according to which said piston is provided with a valve inits head and a valve stem extending from said valve toward said cam, andsaid cam has at last two cam surfaces, one of which is in contact withsaid drive means so that said cam is driven by said pistons, and one ofwhich is in contact with said valve stems to actuate said valves.

2. Internal combustion engine according to claim 1 in which the valvesin the piston heads are intake valves and exhaust valves are located inthe walls of the cylinders.

3. Internal combustion engine according to claim 1 in which said drivemeans comprises a pair of rollers carried by each piston and spacedaxially of said shaft, and said cam has two correspondingly spaced camsurfaces in contact with said rollers and embracing a third surface incontact with said valve stems.

4. Internal combustion engine according to claim 1 in which both theintake and exhaust valves for each cylinder extend through the piston inthat cylinder, and said cam comprises a first cam surface which contactsthe drive means carried by pistons, a second cam surface which actuatesthe intake valves, and a third cam surface which actuates the exhaustvalves, said second and third cam surfaces being axially spaced fromeach other.

which the ratio between the stroke of said pistons, the radius of saidcircle, and the radius of curvature of the cam surfaces between saidlobes is l:l.5:l.

8. An internal combustion engine as claimed in claim 7 in which theratio between the stroke of said pistons and the radius of curvature atthe high point on each lobe is 4:1.

9. Internal combustion engine as claimed in claim 8 in which the ratiobetween the stroke of said pistons and the radius of the rollers carriedby said pistons is 2: l.

1. In an internal combustion engine comprising a cylinder block, an evennumber of cylinders in said block arranged in a circle, said cylindersbeing positioned in diametrically opposed pairs, a piston in eachcylinder, means connecting the pistons of each pair to each other, ashaft rotatably mounted in said block and carrying a multilobe cam, anddrive means carried by each piston in contact with said cam, theimprovement according to which said piston is provided with a valve inits head and a valve stem extending from said valve toward said cam, andsaid cam has at last two cam surfaces, one of which is in contact withsaid drive means so that said cam is driven by said pistons, and one ofwhich is in contact with said valve stems to actuate said valves. 2.Internal combustion engine according to claim 1 in which the valves inthe piston heads are intake valves and exhaust valves are located in thewalls of the cylinders.
 3. Internal combustion engine according to claim1 in which said drive means comprises a pair of rollers carried by eachpiston and spaced axially of said shaft, and said cam has twocorrespondingly spaced cam surfaces in contact with said rollers andembracing a third surface in contact with said valve stems.
 4. Internalcombustion engine according to claim 1 in which both the intake andexhaust valves for each cylinder extend through the piston in thatcylinder, and said cam comprises a first cam surface which contacts thedrive means carried by pistons, a second cam surface which actuates theintake valves, and a third cam surface which actuates the exhaustvalves, said second and third cam surfaces being axially spaced fromeach other.
 5. Internal combustion engine according to claim 4comprising two first cam surfaces axially spaced from each other by thesecond and third cam surfaces and said drive means comprises rollersmounted on the pistons in contact with said first cam surfaces.
 6. Aninternal combustion engine as claimed in claim 1 comprising fourcylinders in which said cam has three identical equally spaced lobes,the tips of which are tangent to a single circle.
 7. An internalcombustion engine as claimed in claim 6 in which the ratio between thestroke of said pistons, the radius of said circle, and the radius ofcurvature of the cam surfaces between said lobes is 1:1.5:1.
 8. Aninternal combustion engine as claimed in claim 7 in which the ratiobetween the stroke of said pistons and the radius of curvature at thehigh point on each lobe is 4:1.
 9. Internal combustion engine as claimedin claim 8 in which the ratio between the stroke of said pistons and theradius of the rollers carried by said pistons is 2:1.